Pre- and Post-Transfer Probiotic Conditioning with Sanolife® PRO FMC in Asian Seabass (Lates calcarifer): Impacts on Gut Health, Microbiome Composition, Growth, and Survival

A commercial field trial in Southeast Asia evaluated Sanolife® PRO FMC, a multi-strain Bacillus probiotic (≥1 × 10¹¹ CFU/g), as a pre- and post-transfer dietary supplement in Asian seabass (Lates calcarifer). Juvenile fish (~69 g) received a 6 mm transfer diet with or without PRO FMC (0.5 g/kg) for 20 days onshore prior to sea transfer (~116 g) and for 35 days in offshore marine cages. Survival was excellent (>99.8%) across all groups. Probiotic-supplemented fish achieved a significantly improved biological FCR (1.47 vs. 1.53; p=0.04) and trended toward higher final body weight (168 g vs. 161 g). Standout clinical improvements included reduced tail fin erosion (21% vs. 32% in controls) and markedly reduced gut Vibrionaceae abundance (5× lower pre-transfer; 54× lower at Day 35 offshore). Full-length 16S rRNA sequencing demonstrated increased Shannon diversity and beneficial anaerobes. Furthermore, gut histomorphometry revealed significantly thicker mucosal/serosal walls (243 vs. 163 µm; p=0.008), denser villi, and 25% higher mucus cell density, confirming enhanced gut resilience and nutrient absorption during transfer stress.